Generally, displays for displaying images may include Liquid Crystal Devices (LCDs), electroluminescence display apparatuses, Organic Light Emitting Diode (OLED) display apparatuses, etc. Compared to the other display apparatuses above, the OLED display apparatus may be formed to be lightweight and thin as well as able to be driven with low power and display high-definition images. Accordingly, the OLED display apparatus has been applied to displays for smartphones or monitors, and the applications thereof are expanding.